1. Field of the Invention
The present invention relates to a liquid container for containing recording liquid, such as ink, for example, which is detachably mountable on an ink jet recording apparatus. More particularly, the invention relates to the packaging structure of such liquid container.
2. Related Background Art
Conventionally, for example, there has been proposed the exchangeable ink tank for supplying ink to an ink jet recording head through an ink supply tube, which is structured separately from the ink jet recording head that records on a recording medium by discharging ink. The exchangeable ink tank is provided with an ink supply port for supply ink to the recording head, and an atmosphere communication port that enables the inside of the ink tank to be communicated with the air outside. In many cases, the structure is arranged so as to provide an ink absorbent for the inside of the housing thereof, and retain ink in the ink absorbent.
It is required for the aforesaid exchangeable ink tank to seal the ink supply port and atmosphere communication portion with a sealing member for the prevention of ink leakage at the time of product distribution. More specifically, there has been known the one having the structure in which a flexible sealing member is used to cover the atmosphere communication port and ink supply port, and the portions of the sealing member are adhesively bonded or thermally bonded to the circumferences of the atmosphere communication port and ink supply port, thus keeping the ink tank airtight. As the method for unsealing the ink supply port and atmosphere communication port, it is usually practiced that the user peels off the sealing member directly for the purpose. This packaging mode is inexpensive and makes it possible to keep the ink tank airtight reliably. Therefore, it is adopted for many ink tanks.
However, for the aforesaid conventional ink tank, there is such a case where the adhesive bonding or thermal bonding is given strongly to the sealing member provided for the ink supply port portion in consideration of the rise of inner pressure in the ink tank due to the environmental changes at the time of product distribution. In this case, the user should peel off the sealing member with an extra force, because the force needed to peel off the bonded portion of the sealing member (exfoliative force) is made higher.
In executing an unsealing method of the kind, the force used for peeling off the sealing member is opened so that the sealing member is removed form the ink tank vigorously. As a result, there is a fear that the ink, which has been airtightly kept by the sealing member, may splash to stain the user's hand or objects that surround the ink tank in some cases.
There are two mechanisms that may cause ink to splash at the time of unsealing the seal. The first is the ink splashes between the ink absorbent and the sealing member, and the second is the splashes of ink that adheres to the sealing member.
As shown in FIGS. 9A, 9B, and 9C, the first one acts in the direction in which the inner volume of an ink tank 51 expands when a sealing member is vigorously separated from the ink supply port. Also, by the inertia exerted by the separation of the sealing member 52, ink 54 existing between the ink absorbent 53 and the sealing member 52 is drawn to follow the sealing member 52. In this case, ink thus drawn is broken eventually at the last. Then, the ink droplets 54, which do not adhere to either side of the ink absorbent 53 or the sealing member 52, are separated and caused to splash out.
Also, as shown in FIGS. 10A, 10B, and 10C, the second one may take place in such a manner that immediately after the sealing member 52 is unsealed, the sealing member 52 is snapped to flutter instantaneously when the sealing member 52 bonded to the ink supply port 55 is separated from the ink supply port 55, and the ink droplets 54a adhering to the sealing surface splash in some cases.
In order to prevent ink from splashing at the time of unsealing the sealing, there is a structure as shown in FIGS. 11A and 11B, in which a cap 62 is welded to an ink supply port 61, thus keeping the ink tank 63 airtight. When this ink tank is unsealed, the cap is turned in the direction different from the one in which the cap 62 is detached so as to shear the welded portion 64. After that, the cap 62 is taken away. Therefore, when the cap is unsealed, the voluminal expansion does not occur inside the ink tank 63. Also, there is no vigorous unsealing, because the cap 62 is detached after the welding is opened. With unsealing means of the kind, a cap is turned to be unsealed, thus making it possible to prevent the ink splashing that tends to take place in the case where the sealing member shown in FIGS. 10A to 10C is used for opening means.
Also, for this cap, the structure is arranged so as not to provide any gap between the ink absorbent in the ink tank 63 and the cap 62 of the ink supply port 61. In this way, a devise is given to minimize the presence of free ink inside the cap before it is unsealed.
Nevertheless, there is an action to “twist” the cap for unsealing the aforesaid ink tank. This “twisting” action is such as to pinch the cap with fingers, and turn the wrist. Therefore, this action of turning the wrist or “twisting” is a difficult one for children, aged persons, or a user who has difficulty in using his hand or wrist. For that matter, it has been required to provide a simpler and more convenient mode of ink tank package.